Natalie Teeger is a single mom with a young daughter. When a man breaks into her house, she's forced to kill him in self-defense.
Meanwhile, Adrian Monk is dealing with Sharona having run off to remarry her ex, and he's interviewing nurses to replace her. When he meets Natalie, he becomes convinced that she is the woman for the job.
Tropes for this episode include:
- Always Murder: Subverted; it's one of the main characters (the newly-introduced Natalie) who kills someone, and even then purely in self-defense. The villains' plot merely involves committing theft.
- Analogy Backfire: Natalie's boss tries to justify that she can afford to miss her own daughter's science fair to work overtime. He points out he has a son and can afford to work overtime, to which Natalie points out that his son is a full-grown man in jail.
- The Cuckoolander Was Right: Zig-Zagged. Randy theorizes that the intruders were after Mr. Henry because he swallowed a diamond. It's actually not that far from the truth; Mr. Henry's aquarium contains a million-dollar space rock, and the intruders were after that and not the fish.
- Earn Your Happy Ending: Natalie gets a new job and finds the intruder. Monk finds an appropriate replacement for Sharona, and Mr. Henry is saved.
- Epic Fail:
- It takes the right amount of ineptitude to pull a fish out of an aquarium accidentally. And also to run off with the fish.
- Stottlemeyer borrows a homemade fire extinguisher from a middle schooler to put out a fire. While the device does work, the kid filled it with turpentine, a flammable fluid.
- Extremely Cold Case: While at the museum with Natalie, Adrian notices wounds on the skeleton of a Neanderthal that the staff never noticed, and realizes he was murdered. Natalie of course, doesn't really care and just wants Monk to focus on her case. Adrian truly cannot go anywhere without stumbling across a murder.
- Friend-or-Idol Decision: When faced with retrieving the moon rock or saving Mr. Henry, Monk chooses to rescue the little goldfish and return him safely to his tank, knowing the sentimental value Julie has for him. Fortunately, the thief had knocked himself senseless moments beforehand, and Stottlemeyer shows up in time to apprehend him before he can escape with the rock.
- Hastily Hidden MacGuffin: Some men show an unusual interest in Julie's aquarium. Turns out they had stolen a million-dollar moon rock from a museum but could not get it out because the guards were searching everyone so they put it in one of the aquarium kits in the gift shop. When they returned to retrieve the rock, they found that Julie had bought the kit.
- He's Back!: With Sharona gone, Monk is almost reclusive again. Spending time with Natalie and Julie allows him to go back to being a detective again, which Stottlemeyer even comments on.
- Jerkass:
- The nurse who Monk interviews tells him bluntly that "it's all in your head" and there's nothing wrong with him. Then she smokes when he's clearly not comfortable with it.
- Natalie's boss shows no empathy to her for missing work even though it was because she killed a man who broke into her home in self-defense. He also doesn't show any empathy when Natalie asks for another day off work to attend her daughter's science fair.
- Lies to Children:
- When he realizes that he talked about Natalie being on the pill in front of Julie, and seeing Natalie's embarrassed anger, Monk tries to claim the packet of pills are Tic Tacs. Julie doesn't buy it.
- More seriously, Natalie has been replacing Mr. Henry every time he's died because she doesn't want Julie to lose the last connection to her father.
- "Not So Different" Remark:
- Stottlemeyer commiserates with Natalie when she mentions that her most valuable belonging is her child Julie.
- Monk empathizes with a parrot at a pet shop who has lost his mate. This in turn causes Natalie to realize that both she and Monk have lost their spouse.
- Papa Wolf: Monk has spent several days learning how important Mr. Henry is to Julie. He chases down one of the crooks when hearing Julie shout, "He stole my fish!" and rescues Mr. Henry rather than go for the priceless rock. This ends up saving the fish and convinces Natalie to take Monk's job offer because as Julie puts it, "Daddy" would have done the same thing.
- Punny Title: "Red Herring" refers to Mr. Henry, a red goldfish. He's also the red herring in that Monk and the police assume that the intruders were after the fish, when they were after a rock in the fish's aquarium.
- Reasonable Authority Figure:
- When Natalie kills the man intruding in her house, Stottlemeyer doesn't charge her with a Crime of Self-Defense, and has Monk work to find out why the man was breaking in.
- Julie's science teacher. He correctly points out that a fish can't live for as long as Mr. Henry supposedly has, and is satisfied when Natalie confesses that he's right, and Julie doesn't know that Mr. Henry has been replaced multiple times. When he hears that Julie doesn't know about the replacements, he allows her to compete in the science fair, on the condition that she can't accept any prizes.
- Red Herring: The "red herring" in the title is Mr. Henry. Literally, as Monk and everyone is initially led to believe Mr. Henry is the one the burglars are after.
- Replaced with Replica: Peck stole the moon rock from the museum and replaced with a duplicate from another exhibit so no one would ever know the rock was stolen.
- Replacement Goldfish:
- A literal case; Mr. Henry has been replaced several times so that Julie never has to know that her fish, a present from her missing father, died a long time ago.
- Subverted with Natalie, who while taking over Sharona's role as Monk's assistant, is a different person entirely from her.
- Shout-Out: The way Natalie kills the intruder is a reference to Dial M for Murder.
- Smile of Approval: Monk briefly displays one when Natalie dismisses the museum worker dressed as a white blood cell.
- Spanner in the Works: The culprit had stolen an expensive moon rock and hidden it in an aquarium set in the gift shop to be retrieved later. Unfortunately for him, an unwitting Julie had bought the set before him, forcing him to try and steal it from the Teegers.
- Tragic Keepsake: Mr. Henry, Julie's marble fish. It was her father's last gift to her before he died.
- Uncatty Resemblance: Monk notices a lot of similarities between himself and "Sgt. Pepper", a bird in a pet store who obsessively cleans his cage and hasn't been the same since his mate died.Natalie: What was her name?
Monk: Trudy. - Villain Ball: So you create a distraction to steal a rock from an aquarium, but then you accidentally grab the fish in the tank. Then you run off with both in a panic. Julie's alarmed cry of, "He stole my fish!" gets Monk to chase him down.
- You Are Better Than You Think You Are: Monk tells Natalie this when she at first turns down his offer to become his assistant.
